connection cable: ¼” (6.35 mm) stereo jack plug (connected ex works), unbalanced
4.4 mm stereo jack plug, balanced
USB flash drive (SD-U16L version) with instruction manual (as PDF file) and individually diffuse-field frequency response curve
There are no two ways about it - the Sennheiser HD820 are the best, all-around, closed-back headphones I’ve heard.
Putting them on doesn’t fill me with the same sense of anticipation that I get any time I’m within reach of a Focal Utopia. Listening to music with them doesn’t make my heart beat faster or my head bop. And, most importantly, I’d prefer a pair of the cheaper and superior HD 800 S over the pricier and imperfect HD820 a hundred times out of a hundred.
-The Verge(Sep 2018)
The HD820 are pricey, but they are the most capable pair of closed-back headphones we’ve tested